Photos or spoken words enhance our gut sense that a statement is true.

True or false: the macadamia nut is closely related to the peach. Most of us don't have the sort of background information that will let us answer that with confidence. Still, we have a gut feeling about the answer—"Nuts and fruit? Probably not." These sort of gut reactions to things can be key to helping us navigate through a world where we often don't have complete information.

So it's a bit disappointing to find out how easily our gut feelings can be manipulated. All it takes is a bit of extraneous information—a picture of macadamias or a verbal description of them—and we're far more likely to assume that a statement is true.

The authors, based in New Zealand and Canada, performed an "alive or dead" test, showing the names of minor celebrities and asking undergraduates whether the person was still alive. In half the cases, they also showed a photo of the person. When the photo was present, people were more likely to answer that the statement was true.

The obvious explanation for this is that none of the photos were of a corpse, and seeing a person alive would almost certainly bias the participants toward thinking the person was alive. So, they switched the questions, asking another group whether they thought the person was dead. As it turned out, the photo also caused people to evaluate the statement as true, and answer that the person was no longer alive.

To make sure this didn't only work with people, the authors switched to true/false trivia questions, like the macadamia example mentioned above. Again, photos (in this case, images of the subject of the question) caused people to answer "true" more often than they did in a control quiz. And it wasn't just images. They could get a similar effect by reading a short description of the person in question.

The authors equate this with the "truthiness" popularized by Stephen Colbert, going so far as including the term in their paper's title. But it seems to me that they're not really related. Truthiness seems to be something that feels true despite facts indicating the contrary. Here, people typically didn't have enough information to make a call on the question, and were forced to rely on their instincts.

The authors spend a bit of time discussing why this sort of truth bias might arise. In cases where we have rich information—a photo or detailed description of something—it's easier to pull additional information out of our memory. So, even if a photo doesn't tell us much about whether the person is alive, it does make it easier to retrieve relevant information on them—if they're wearing a suit in the photo, we might reason they're a political or financial figure, etc. When the information flows that readily, we're more likely to conclude that we're familiar with the question that's being posed, and will then tend to conclude it's true.

Oh, and macadamia nuts? They do not appear to be very closely related to peaches.

33 Reader Comments

In perhaps the most stunning illustration of the study, the authors posted the results of their article to Ars Technica with the lead question at the top of the page, and secretly monitored user clicks.

The result?

Most of us scrolled to where we might find the answer, and then ignored the article. Bravo, Psychonomic Bulletin and Review. An elegant and valid experiment.

In perhaps the most stunning illustration of the study, the authors posted the results of their article to Ars Technica with the lead question at the top of the page, and secretly monitored user clicks.

The result?

Most of us scrolled to where we might find the answer, and then ignored the article. Bravo, Psychonomic Bulletin and Review. An elegant and valid experiment.

I'd say slightly botched because I'm not too clear what question I was supposed to be finding the answers for:

Are macadamia nuts related to peaches?Is Ken Ober dead or Canadian?Did it happen?

I think this is one of those unsurprising things that most people would assume to be the case (probably because the saw a picture once..), but never had actual research to support it. As others have mentioned, there are potential problems or other biases that could impact though, but this might spur future study.

The authors spend a bit of time discussing why this sort of truth bias might arise. In cases where we have rich information—a photo or detailed description of something—it's easier to pull additional information out of our memory. So, even if a photo doesn't tell us much about whether the person is alive, it does make it easier to retrieve relevant information on them

The conclusion doesn't make much sense to me. If having a picture stimulated memory retrieval then we wouldn't expect the participants to more often answer "true" to the question whether asking if the person was alive or if the person was dead.

I read about a study a little while back that showed that giving people even simple mental tasks caused the participants to be much more agreeable/suggestible. I think they had the participants remember a relatively short string of numbers and then asked questions. They would agree much more often while remembering the numbers. So maybe it is similar in this case. The presentation of other information (in this case visual information) causes some of the brain's attention to be diverted to processing of that info, leading to less attention given to processing the question. Why we default to agreeable, I have no idea.

The authors spend a bit of time discussing why this sort of truth bias might arise. In cases where we have rich information—a photo or detailed description of something—it's easier to pull additional information out of our memory. So, even if a photo doesn't tell us much about whether the person is alive, it does make it easier to retrieve relevant information on them

The conclusion doesn't make much sense to me. If having a picture stimulated memory retrieval then we wouldn't expect the participants to more often answer "true" to the question whether asking if the person was alive or if the person was dead.

You underestimate the power of random images to get people to, themselves, behave randomly in response.

Pictures of cats give me the the uncontrollable urge to give boolean answers to A|B questions all the time.

The authors spend a bit of time discussing why this sort of truth bias might arise. In cases where we have rich information—a photo or detailed description of something—it's easier to pull additional information out of our memory. So, even if a photo doesn't tell us much about whether the person is alive, it does make it easier to retrieve relevant information on them

The conclusion doesn't make much sense to me. If having a picture stimulated memory retrieval then we wouldn't expect the participants to more often answer "true" to the question whether asking if the person was alive or if the person was dead.

The study didn't present non-probative information and ask "if the person was alive or dead".

What researchers did, is post a single statement (not a dichotomous choice) for T/F evaluation, along with a photograph.

What they found is that, when a non-probative photograph is present, participants are more likely to judge a question (or statement) as "true".

So, when we have richer information sources, but no more data about a topic, we're biased toward belief.

The authors spend a bit of time discussing why this sort of truth bias might arise. In cases where we have rich information—a photo or detailed description of something—it's easier to pull additional information out of our memory. So, even if a photo doesn't tell us much about whether the person is alive, it does make it easier to retrieve relevant information on them

The conclusion doesn't make much sense to me. If having a picture stimulated memory retrieval then we wouldn't expect the participants to more often answer "true" to the question whether asking if the person was alive or if the person was dead.

The study didn't present non-probative information and ask "if the person was alive or dead".

What researchers did, is post a single statement (not a dichotomous choice) for T/F evaluation, along with a photograph.

What they found is that, when a non-probative photograph is present, participants are more likely to judge a question (or statement) as "true".

So, when we have richer information sources, but no more data about a topic, we're biased toward belief.

I get how the test was performed (even if that didn't come through so well in my post). I guess it was just the conclusion that "making relevant information easier to retrieve" somehow causes this bias didn't make much sense. Relevant information in my head may include factual information such as whether I heard that the person died. If that is the case then I would have thought that additional "retrieved information" should generally skew me closer to the correct answer.

On the other hand, I think this study may explain why so many people nod along during power point presentations even when it is clear they have no idea what is being said. Note to self, include more pictures...

I get how the test was performed (even if that didn't come through so well in my post). I guess it was just the conclusion that "making relevant information easier to retrieve" somehow causes this bias didn't make much sense. Relevant information in my head may include factual information such as whether I heard that the person died. If that is the case then I would have thought that additional "retrieved information" should generally skew me closer to the correct answer.

On the other hand, I think this study may explain why so many people nod along during power point presentations even when it is clear they have no idea what is being said. Note to self, include more pictures...

The effect is present for subjects with which we are unfamiliar (i.e., we lack knowledge). If you already know whether or not someone is dead or alive, all else being equal, it doesn't bias your tendency to agree.

Also, WRT graphics, the effect is specific to photographs. From the paper:

People often regard photos as evidence of reality. Indeed, Kelly and Nace (1994) showed that people trust photos even when they distrust the source in which they appear (e.g., the National Enquirer). Perhaps related to this finding, McCabe and Castel (2008) found that in contrast to photo- realistic images of the brain, bar graphs did not enhance ratings of the scientific reasoning in an article (see also Keehner, Mayberry, & Fischer, 2011).

The authors spend a bit of time discussing why this sort of truth bias might arise. In cases where we have rich information—a photo or detailed description of something—it's easier to pull additional information out of our memory. So, even if a photo doesn't tell us much about whether the person is alive, it does make it easier to retrieve relevant information on them

The conclusion doesn't make much sense to me. If having a picture stimulated memory retrieval then we wouldn't expect the participants to more often answer "true" to the question whether asking if the person was alive or if the person was dead.

I read about a study a little while back that showed that giving people even simple mental tasks caused the participants to be much more agreeable/suggestible. I think they had the participants remember a relatively short string of numbers and then asked questions. They would agree much more often while remembering the numbers. So maybe it is similar in this case. The presentation of other information (in this case visual information) causes some of the brain's attention to be diverted to processing of that info, leading to less attention given to processing the question. Why we default to agreeable, I have no idea.

Maybe because when you agree you don't really have to think about it? The same way most people will nod and say, "yep" and "uh huh" when you are talking to them and they are not listening.

Anymore I personally have grave doubts about studies that are done only on undergraduates. I always wonder how many of them just said "true" over and over to get the test done, get their required credit, and get the hell out of there. Perhaps the tests control for things like that; I admit that I don't know.

Some of these tests I'd like to see performed also on a group of elderly folks in retirement homes, where instead of wanting to end the test quickly like an undergrad, they're far more likely to want to prolong the test because they're bored of bridge.

I'm not saying these types of tests aren't valuable. I just hesitate at generalizing from "undergrad students" to "humans in general".

Not sure if this is the same thing but I post on AVSForum and on one of the boards you can post about your setup (home theater system, etc.). If someone posts about their setup but provides no pictures, the tendency of the postings by other members are to ask for pics or it didn't happen. Post pics and it's instantly more believable.

Anymore I personally have grave doubts about studies that are done only on undergraduates. I always wonder how many of them just said "true" over and over to get the test done, get their required credit, and get the hell out of there. Perhaps the tests control for things like that; I admit that I don't know.

Some of these tests I'd like to see performed also on a group of elderly folks in retirement homes, where instead of wanting to end the test quickly like an undergrad, they're far more likely to want to prolong the test because they're bored of bridge.

I'm not saying these types of tests aren't valuable. I just hesitate at generalizing from "undergrad students" to "humans in general".

What these kinds of studies demonstrate, rather than generalizability, is that the general cognitive model under study, is (or isn't) valid.

Some research has examined the difference between university populations, and those of older, non-university populations, and found that results often "soften". That is, IIRC, relationships typically hold, but the magnitude often differs.

Of course, it's not the case for every study, and will vary by research subject.

I read about a study a little while back that showed that giving people even simple mental tasks caused the participants to be much more agreeable/suggestible. I think they had the participants remember a relatively short string of numbers and then asked questions. They would agree much more often while remembering the numbers. So maybe it is similar in this case. The presentation of other information (in this case visual information) causes some of the brain's attention to be diverted to processing of that info, leading to less attention given to processing the question. Why we default to agreeable, I have no idea.

Maybe because when you agree you don't really have to think about it? The same way most people will nod and say, "yep" and "uh huh" when you are talking to them and they are not listening.

And agreeing with people or giving them their way tends to end the interaction quicker so you can resume the cognitively demanding task at hand.

I'm busy at work..."Hey, can you file those TPS reports by Thursday?""Sure, no problem, Thursday"*Encounter ends, I go back to what I was doing*

I'm busy at work..."Hey, can you file those TPS reports by Thursday?""Ah, that's gonna be tricky, got stuff to do""Come on, remember that favour I did for you?""Sure, but..."*Encounter continues for the next hundred years, I forget where I was in my Twitter feed*

"Truthiness" is about replacing factual truthfulness for a gut feeling. In other words elevating what you feel to be equally or more valid than what is true. Maybe something is true and maybe it isn't, but that's not as important as what I feel like.

Spoken words are only strong reinforcement for some people. I have a son that whose acceptance of a statement is GREATLY reinforced by it being written word rather than spoken.

But given that his language developed via written as the lead, rather than verbally as most of us have, I think it adds to the weight supporting these findings rather than subtracting and may provide some insight as to why this effect occurs.

It would be interesting to see receptiveness of bilingual/multilingual people to their original language compared to messages received in their secondary languages.

The authors spend a bit of time discussing why this sort of truth bias might arise. In cases where we have rich information—a photo or detailed description of something—it's easier to pull additional information out of our memory. So, even if a photo doesn't tell us much about whether the person is alive, it does make it easier to retrieve relevant information on them

The conclusion doesn't make much sense to me. If having a picture stimulated memory retrieval then we wouldn't expect the participants to more often answer "true" to the question whether asking if the person was alive or if the person was dead.

You underestimate the power of random images to get people to, themselves, behave randomly in response.

Pictures of cats give me the the uncontrollable urge to give boolean answers to A|B questions all the time.

Cashews grow out of the bottom of a fruit called the cashew apple, better known in central America as "marañón". The juice of it tastes kinda *like* a peach, crossed with a mango. If only cashews and macadamia nuts were related, then could we get a true?